This invention generally relates to man-machine interface protocols, and more specifically, to such a protocol for transiently shown control switches that are visually displayed on a video screen or other similar display means.
In many situations, a multitude of remote or peripheral work units are controlled or operated from a central control unit. This central control unit may have a multitude of control switches to at least actuate and deactuate the peripheral work unit, and commonly to also cause those work units to perform various functions or tasks. The control unit may, in addition, have one or more gauges or video screens to display parameters or other data relating to the remote work units.
Recently, procedures have been developed to control the operation of such peripheral work units by means of switches transiently shown on a video screen. With this procedure, a multitude of switches are displayed on a video screen, with each of these switches being used to control the operation of an associated peripheral work unit. When one of the displayed switches is touched, a signal is generated identifying the area of the screen being touched. This signal is conducted to a central processor that identifies the switch being engaged and the work unit associated with that switch; and the central processor, in turn, generates a signal that is conducted to that associated work unit to change the state of the work unit. For example, this signal from the central processor may be used to actuate or deactuate the work unit.
A major advantage of this procedure is that the central control unit may be made very compact because a single, relatively small video screen may be used to show all, or most, of the switches used to control the peripheral work units. To elaborate, while only a limited number of switches can be shown on the video screen at any one time, the display on the screen can be changed to show different sets of switches at different times so that, over time, a very large number of switches can be shown on just one video screen. There is a disadvantage with the above-discussed procedure in that, in comparison to conventional prior art switches such as toggle switches, the positions of the transient switches displayed on the video screen do not change as the states of the associated work units change, and thus the positions of the displayed switches do not indicate the states of the associated work units. This may make it difficult for an operator to determine the current states of those work units.